We went with an aerobic treatment system (ATS) rather than a septic tank for our sewage system because it is supposed to result in cleaner effluent and we wanted to use the treated (and post sand filtered) effluent on the land for watering (non-edible) plants, etc.

(You can see all of the posts about the sewage system we installed by clicking here.)

The final step was to install the air pump that turns the sewage system aerobic.

Basically, the air pump they sold us for it is probably the same kind you might use on a koi pond:

K’Tanawat ran around today to find the couplings to connect it to a pipe and connect the pipe to the ATS tank. Since it is just blowing bubbles to aerate the effluent and stimulate aerobic bacteria (which seem to be more “active” than anaerobic bacteria in digesting the incoming sewage), and the pipe only goes about 1 or 1.5 meters deep in the tank, I’m not too worried about needing high pressure pipes. (You can easily stop up the air pump with one finger and not even pressing very hard.)

The air flow goes into the ATS via an inlet for this (that had PVC sized threads, so that is why we went with PVC):

This inlet runs to a pipe that goes down into the tank. I’m curious whether they have any airstone or other small holed outlet in order to create a larger number of smaller bubbles. As we’ve learned from the pond aeration, this is much more efficient at oxygen absorption in liquids. Hopefully this is all taken care of for us.

So now we just need to get our electricity from the utility and this will be on all the time.

A side note…
I actually intended to use the smaller of the two DC air pumps we bought off eBay recently for this so that it could be powered by solar. But that pump was many times louder, uses many times more electricity and blows many times more air. So the smaller one turned out to be plenty good enough for the pond, which is actually what I bought the larger one for. The AC pump that came with the ATS is much quieter, which is important since it will be installed under one of the bedrooms. So with regards to moving this off grid, our current plan is to run this air pump off of AC for the time being, but wire it up such that if we are successful in building our own inverters, we will switch it over to the DC solar powered circuit, but still using the AC pump.

I need a few successes similar to this one on the pond circulation pump before I can say with certainty that we can build a reliable (and safe!) inverter. Until then, the ATS air pump will simply run on AC power from the grid.